Metabolisms of ROS and membrane lipid participate in Pestalotiopsis microspora-induced disease occurrence of harvested Chinese olives

Pestalotiopsis microspora (P. microspore) is the main pathogenic microorganism causing fruit spoilage and rot in postharvest Chinese olive (Canarium album L.). The effects of P. microspore inoculation on disease occurrence of harvested Chinese olives with a specific focus on ROS and membrane lipid metabolisms were explored. The results showed a higher fruit disease index in P. microspora-infected samples. Notably, P. microspora-infected samples exhibited higher ROS levels, coupled with the lower AsA and GSH contents, the reduced ROS scavenging enzyme activities, a decreased reducing power, and a lower ability for scavenging DPPH radicals. Furthermore, the inoculated Chinese olives displayed higher cell membrane permeability and MLMREs activities, higher values of MDA, DAG, and SFAs, but lower PC and PI contents, USFAs, U/S, and IUFA. Taken together, these findings strongly suggested that the aggravated disease development in postharvest Chinese olives after P. microspore inoculation could be attributed to an enhanced peroxidation of membrane lipids due to the dropped capability to eliminate ROS.